/Engine/Source/Editor/CurveEditor/Public/CurveModel.h
Get the interpolation mode to use at a specified time
Interpolation mode to use at that frame
virtual TPair< ERichCurveInterpMode, ERichCurveTangentMode > GetInterpolationMode ( const double & InTime, ERichCurveInterpMode DefaultInterpolationMode, ERichCurveTangentMode DefaultTangentMode ) const